ATOMIC MINERALS DIRECTORATE FOR EXPLORATION AND RESEARCH

General Information

The New Delhi office was set up during 1949 as the AMD headquarter,which was shifted to Hyderabad in 1974 and the office at New Delhi remained as the headquarter for Northern Region. Rajasthan was initially a part of the Northern Region, but during 1988 it was carved out to form a separate region as Northwestern Region (now Western Region).

Broad Geological features

The Northern Region comprises of the  great Himalayan mountain ranges exposing igneous and metasedimentary rocks of various ages in the Higher and Lesser Himalayas, the trans-Himalayan sedimentaries,the Siwalik sediments, the vast Gangetic alluvial tracts and the Archaean granitoids and Proterozoic sediments in the south.

The Higher Himalayas : comprises of granite gneisses and high grade metamorphic rocks, also known as the Central Crystalline axis. To the south, across the Main Central Thrust (MCT), the Lesser Himalayas are represented by metasedimentary and metabasic rocks with some well known nappes and Klippes, with or without intrusive granites. The Main Boundary Thrust(MBT) separates the Lesser Himalayan rocks from the Siwalik belt.

The Siwalik belt : extending from Jammu & Kashmir through Himachal Pradesh to Uttarakhand is a prominent geological feature of the Region. The Siwalik sediments are divided into Lower Siwalik (mainly argillaceous), Middle (arenaceous with shaly inter layers) and Upper Siwalik (conglomerates with sandy lenses).

The Himalayan Frontal Fault (HFF) to the South separates the Siwaliks from the Indo-Gangetic plains.

Further to the south of the Indo-gangetic plain, the Proterozoic Bijawar - Gwalior - Vindhyan groups of rocks are exposed over the Bundelkhand granitic complex as basement. The southern margin of the Vindhayan basin is bound by the Mahakoshal Group and Chhotanagpur granite gneisses.

Summary of Investigations:Important finds

Although no economically viable deposit has been delineated here so far, a large number of important uranium occurrences have been discovered in almost all geological domains of the Northern Region.

In the Upper-Middle Siwalik transition zones of Himachal Pradesh, Haryana, Uttarakhand and J&K, lenticular uraniferous bodies, both in the sandstones as well as in conglomerates occur over large areas. The lenses are a few  metres to few tens to hundred of  metres  in dimension with low average grade.A large number of blocks have been drilled and exploratory mining was also carried out in three blocks, viz. Asthota, Khya and Andalada, Hamirpur Dt, Himachal Pradesh. Rajpura is the best known occurrence so far, with a low reserve. Other occurrences of similar nature are in Dhanaur and Naugajia Rao—Shakumbari Rao areas in Uttarakhand, Maler and Thein in J&K and Morni in Haryana.

In the pre-Siwalik transition sediments also a number of anomalies have been located in the Dharamsala Group in Solan and Mandi Districts, H.P. out of which Tileli is the largest occurrence so far identified. At Tileli, uranium mineralisation associated with lithic arenites at the contact of Lower & Upper Dharamsala formations, was located over a strike length of 500m x 10m, that was traced down to a vertical depth of 300m by exploratory drilling. Further drilling is constrained due to steep topography and unstable terrain.

While the gnessic rocks of the Higher Himalayas show profuse development of secondary minerals, e.g. as in Chaura, Kinnaur Dt, H.P., significant uranium mineralisation associated with sheared gneisses and quartzites of Rampur Group have been traced in several localities in the Lesser Himalayas, across the MCT, important among which are in Kasha, Kandi andKaladi,Shimla district, Himachal Pradesh. The mineralisation occurs in the form of small veinlets along the fractures. Yellow cake has been recovered from the uraninite veinlets of Kandi area by small scale mining and heap leaching.

Similar uranium occurrences have also been located in the Berinag quartzites of Uttaranchal. Shear-controlled uranium mineralisation of significant dimensions and grade are hosted by chlorite-sericite schists of Pokhri area, Chamoli Dt, and by granite gneisses in Brijranigad area,Tehri Dt, Uttaranchal.  Exploration in the Himalayas are greatly hindered by eological complexities and lack of infra-structural facilities.

In parts of the peninsular India, uranium mineralisation was observed at a number of places like Naktu,Kudar,Nawatola-Dhanbadua etc in cataclastic breccia and migmatites in Sonbhadra district, Uttar Pradesh. The area forms part of Chhotanagpur Granite Gneiss Complex. Exploratory drilling was carried out in these areas but had to be discontinued due to poor grade and tonnage.

Uranium mineralisation was also found associated with fracture-filled bitumen in chloritic shale, Bandai sandstone and Rohini carbonate of Bijawar Group around Sonrai, Lalitpur district, Uttar Pradesh. Exploratory drilling indicated that the mineralisation is not correlatable.

Present thrust areas of investigations

The present areas of investigations are mainly concentrated in Gwalior-Bijawar and tracts of Vindhyan basins in parts of Madhya Pradesh for locating Proterozoic unconformity type of deposits & as well as in Siwalik and pre-Siwalik formations in parts of Himachal Pradesh for locating sandstone type of deposits. Stratigraphic drilling is in progress in parts of Haryana  to understand the geological setting and trace the northern continuity of the albitite line from Rajasthan where significant uranium mineralisation has been established in the albitised metasediments of Rohil area.

Other facilities available at Northern Region

The Region is equipped with

• Physics Laboratory
• Chemistry Laboratory
• Petrology Laboratory